Unit installation

FS 70 Installation Instructions
974-24007001/4.1 61
The plastic strain relief attached to the trawl cable is now placed in
the trawl unit housing containing the electronics and the excess cable
is routed in the housing. Care must be taken to insure that all cables
within the trawl unit housing are properly placed to avoid being
pinched and possibly damaged. The top half of the trawl unit
housing is then placed on top and the two halves are secured together
with the bolts supplied. Finally, the dome is secured over the
Vertical Sonar Head transducer with four additional bolts.
The fully assembled trawl unit is now ready for mounting to the trawl
head rope in the chosen manner.
4.3.22 Mounting the Catch Sensors
Proper mounting of the catch sensors on the cod-end is shown in
drawing # 830-056482.
The fill of the cod-end and the sensitivity of the sensors are
dependent upon the number of mesh knots between the catch sensor
and the rubber straps. Make sure that the sensor is mounted in the
correct direction with the transducer pointing towards the trawl unit
(the metal lid pointing aft).
WARNING: Make sure that the chains do not strain the net when
the cod-end is being filled with fish. This is controlled by
stretching the net to capacity in the direction which is relevant
AFTER THE SENSORS HAVE BEEN MOUNTED TO THE
TRAWL. The purpose of the chains is to prevent the sensor from
turning, and as an insurance against loss should the rubber straps
break. Mounting the chains too tight can result in the fastening
ears being ripped off.
If a system with four catch sensors has been ordered, sensors
numbered 1 and 2 can be used on the trawl and the other two sensors
kept for reserve.
For deep trawling, and when fish are abundant, it can be
advantageous to mount three or four catch indicators in such a way
that cod-end filling can be monitored continuously to insure that the
trawl is hauled back in time.